A quick win for ministers on air pollution? Cleaner delivery trucks

Environment Secretary Michael Gove has sent out the right signals by announcing a ban on new diesel cars and vans from 2040, with the Scottish government aiming to do likewise by 2032. Despite these appropriate steps, an often-overlooked area- but with a significant and disproportionate negative impact- is transport refrigeration.

We have all seen the refrigerated delivery trucks that transport food and drink from farms and factories to our local supermarkets and restaurants. Many of these use not one, but two, diesel engines- the main engine at the front propelling the truck and the secondary engine keeping the back compartment cold. With extremely weak regulation on the secondary engine, it is allowed to be disproportionately polluting.

In fact, the secondary engine emits six times as much nitrogen oxide (NOx) as the main engine and 29 times as much particulate matter (PM). Drivers of diesel cars and vans will soon be looking to switch to electric or hybrid alternatives- but they will rightly wonder why heavily polluting secondary engines are still allowed on Britain’s roads.

The Dearman engine

To demonstrate the extent of their impact on air pollution, if Britain’s 84,000 transport refrigeration units (TRUs) became zero emission, it would be the particulate matter equivalent of taking 3.8 millionEuro 6 diesel cars off our roads.

Tackling this would be a quick win for government- but how?

Simply put, these secondary engines are also allowed to use red diesel, on which government charges much less fuel duty compared to standard white diesel. This reduced level of tax also means the Treasury foregoes £126 million of revenue. A number of zero emission TRUs are affordably available on the market, but the availability of cheap red diesel disincentivises their take-up.

Ministers are beginning to realise the scale of the problem here and Chancellor Philip Hammond rightly launched a consultation earlier this year on red diesel use in urban areas. He must now go all the way and use his Autumn Budget statement to announce an end to red diesel use in transport refrigeration. Clawing back tax revenue, encouraging a shift to affordable clean alternatives, and making a quick impact all make this a strong and positive measure for him to pursue.